As a printer of the electrophotographic type, there is known a printer that is provided with a photosensitive body and a developer cartridge. The developer cartridge is configured to supply toner to the photosensitive body.
This type of printer is provided with a new product detecting unit used for judging information on the developer cartridge mounted in the printer. Examples of the information include information on whether the developer cartridge is a new (unused) product.
For example, there has been proposed such a laser printer, in which an actuator is provided inside a main casing of the printer. A detection gear is rotatably supported on the developer cartridge. The detection gear is provided with a contact projection for contacting the actuator. When the developer cartridge is mounted in the main casing, the detection gear is driven to rotate, as a result of which the contact projection on the detection gear contacts the actuator and pivots the actuator. The movement of the actuator is detected by an optical sensor. Detection results by the optical sensor are used to judge the information on the developer cartridge.